Dolphins are often regarded as one of Earth’s most intelligent animals, though it is hard to say just how intelligent.

Most dolphins have acute eyesight, both in and out of the water, and they can hear frequencies ten times or more above the upper limit of adult human hearing. Though they have a small ear opening on each side of their head, it is believed hearing underwater is also, if not exclusively, done with the lower jaw, which conducts sound to the middle ear via a fat-filled cavity in the lower jaw bone. Hearing is also used for echolocation, which all dolphins have. Dolphin teeth are believed to function as antennae to receive incoming sound and to pinpoint the exact location of an object. Beyond locating an object, echolocation also provides the animal with an idea on the object’s shape and size, though how exactly this works is not yet understood.

The dolphin’s sense of touch is also well-developed, with free nerve endings densely packed in the skin, especially around the snout, pectoral fins and genital area. However, dolphins lack an olfactory nerve and lobes, and thus are believed to have no sense of smell. They do have a sense of taste and show preferences for certain kinds of fish. Since dolphins spend most of their time below the surface, tasting the water could function like smelling, in that substances in the water can signal the presence of objects that are not in the dolphin’s mouth.

Generally, dolphins sleep with only one brain hemisphere in slow-wave sleep at a time, thus maintaining enough consciousness to breathe and to watch for possible predators and other threats. Earlier sleep stages can occur simultaneously in both hemispheres.   In captivity, dolphins seemingly enter a fully asleep state where both eyes are closed and there is no response to mild external stimuli. In this case respiration is automatic; a tail kick reflex keeps the blowhole above the water if necessary. Anesthetized dolphins initially show a tail kick reflex. Though a similar state has been observed with wild Sperm Whales, it is not known if dolphins in the wild reach this state.The Indus river dolphin has a different sleep method from other dolphin species. Living in water with strong currents and potentially dangerous floating debris, it must swim continuously to avoid injury. As a result, this species sleeps in very short bursts which last between 4 and 60 seconds.

1.    African Elephants are mammals.
2.    They live in herds up of to 40 members.
3.    Elephant have live births like all mammals.
4.    Baby Elephants drink their mothers’ milk.
5.    Male Elephants are called bulls.
6.   Female Elephants are called cows.
7.    Elephants are the largest land mammals.
8.    There are two types of elephants – the Asian and the African elephant.
9.    Elephants eat trees, roots, twigs and leaves.
10.    Elephants are my favourite animals.